Chart for stacking angle iron in a Swag press brake

[Tmate]

The attached chart shows the width of the V for angle iron with various leg lengths. All angle iron shown is 1/4" wall except the largest, which is 3/8". The drawing software added a thousandth or so to some of the dimensions, so they are ball park. Since we are concerned with the inside of the V, we can't use the Pythagorean theorem based on the leg length. We could use the sum of the squares of (each leg minus the wall thickness) to arrive at the square of the V width.

 

[matthewsx]

Interesting, do you stack it like that to get different size bends? Had to look them up and now I think I know what to do with the Enerpak frame I have.

John

 

[Tmate]

My understanding is that you want the width of the V to be about 8 times the thickness of the material. Also, the smaller the angle iron, the tighter the bend. Some people using angle iron for a die machine the inside radius for a tighter bend. You can also machine a bit off the outside of the angle so the pieces of angle iron will fit flush inside each other.

The stacked angle iron pieces need to be close to the same height so the larger outside section doesn't affect the bend before the material reaches the smallest piece you are using.

 

[AGCB97]

Excuse my ignorance but I'm not understanding the purpose for this. Yet I don't want to pass up learning something new.
Thanks
Aaron

 

[Tmate]

This assumes you have purchased a 20 ton press brake from Swag either in kit or pre-welded form. The 3" leg angle iron die that comes with the kit has a large radius in the V. If it was used by itself in bending thin material, the legs would cause the piece to bend into a wide arc. Also, the wide radius would prevent a sharp bend.

The big V in the supplied die is needed for bending thicker material, say 3/8" or more. Swag recommendations that you stack successively smaller angle iron in the V to bend thinner material. The chart, simple as it is, was intended to help fabricators select the right sizes of angle iron to use based on the thickness of the material to be bent. There are different theories as to the best ratio of material thickness to V width, but the consensus seems to be a V width 8 times the material thickness. As stated in the post with the chart, all angle iron shown is 1/4" wall except the largest, which is 3/8".

 

[Tmate]

Correction -- The 3" leg angle iron die comes on the Swag "Heavy Duty" 20 ton brake press. The standard 20 ton brake comes with a 2" die which does not require a stack of angle iron sections to achieve a tight radius with thinner materials.